George Galloway conceded last night that intermediaries in his fund-raising activities could have siphoned off money from Saddam Hussein - but insisted he had never done so.

As the Labour MP fought to counter allegations that he received up to £375,000 a year from the Iraqi regime, Mr Galloway revealed the full amount given to the Mariam Appeal - the organisation he founded to fly a young Iraqi leukemia victim to Britain for medical treatment and which then became a campaign against Iraqi sanctions - and pledged to release further figures today.

Speaking to the Guardian from his holiday home in Portugal, Mr Galloway said there was a "possibility" that third parties had taken money from the former Iraqi dictator.

He also conceded he was open to criticism for collecting money from what he called "unlikely quarters". But he insisted he personally had received "no money from anybody".

Mr Galloway's comments came after the Daily Telegraph printed documents, discovered in a burnt-out foreign ministry building in Baghdad and purporting to be from an Iraqi spy chief, that suggested he had demanded money from the Iraqi regime under the oil-for-food scheme. "Irrespective of the provenance of the documents the material in them is false", the MP for Glasgow Kelvin said yesterday.

There was no evidence he had ever traded in oil, or food, or money, Mr Galloway said. "I have not," he insisted.

Yesterday, the allegations intensified as the attorney general, Lord Goldsmith QC, in his capacity as protector of charities, confirmed he was considering whether to inves tigate claims Mr Galloway had misspent money raised by the Mariam Appeal

It has been alleged that he had spent the money - purportedly intended to treat sick Iraqi children - on extensive travelling expenses. But Lord Goldsmith is taking legal advice to assess if he has the power to investigate the appeal, which has not registered as a charity.

As MPs urged him to throw open the appeal's accounts, Mr Galloway revealed that the Mariam Appeal had received about £800,000 over the past four years. More than £500,000 was provided by the United Arab Emirates and about £100,00 by Saudi Arabia.

The bulk of the remainder had been provided by the Jordanian businessman, Fawaz Zureikat, a long-time opponent of sanctions against Iraq and the campaign's chairman. The rest came from a number of small donors, said Mr Galloway. As for expenditure, £150,000 was spent on the "Big Ben to Baghdad" bus - which travelled from London to Baghdad in 1999 - and about £60,000 on a sanctions-busting flight to Baghdad the following year.

A total of £80,000 was spent on the campaign's offices overlooking Trafalgar Square in central London, £35,000 was spent on three conferences, and £50,000 on sanctions-monitoring publications, publicity and advertisements. Mr Galloway insisted the Great Britain Iraq Society, an organisation linked to the Mariam Appeal and cited by the MP as funding foreign trips in the Commons register of members' interests, had spent just a few thousand pounds in one year.

He added that further "ballpark figures" would be released today in a one-page summary, while more detailed documentation, including bank statements and cheques, would be drawn up later and presented as a "material part" of his libel case against the Daily Telegraph.

The information failed to satisfy colleagues in Westminster, however. Downing Street refused to be drawn on the allegations - with the prime minister's spokesman saying that, with a libel action in the offing, they would not comment on the "serious allegations". But MPs called for him to open the accounts of both the Mariam Appeal and the Great Britain Iraq Society immediately and to explain their connection.

Conservative leader Iain Duncan Smith called for a parliamentary investigation into Mr Galloway's financial affairs. "If he clears his name, then fine.

"But I do think there needs to be an investigation by the privileges committee. If he does not clear his name then he has committed a crime.

"I say crime because if it is true that he took money from the oil-for-food programme, it is a crime against humanity. That was money for food for the people in Iraq, it was not for George Galloway."

Michael Foster, Labour MP for Hastings and Rye and a member of the Commons standards and privileges committee, said the committee - which expects to be called to investigate him - "will want to be satisfied he hasn't received any personal benefit that has not been registered".

He added: "As a colleague, I always think openness is the best policy. If he says he has nothing to hide, I would certainly invite him to produce the accounts at the earliest opportunity," he added.